- 13 -
11-5. Current limit: Phase control only (current detection / alarm output function [optional])
Function for limiting output current to within 0
–
120% of the device’s rated current. Limits current and protects the load if using loads with large inrush
current such as pure metal heaters or lamp heaters.
The device detects output current by built-in CT, and because output is controlled each cycle of the power supply frequency, a difference in actual output
and target output may develop. Sudden change in load while conducting power therefore cannot be handled in some cases.
If using external current limit setting device B
characteristic 10kΩ (VR), allo
cate by key sequence
‘
1-11. Current limit
’
(current is limited to 0
–
100% of
rated current if allocated to VR).
If load of inrush current is large, set the slow-up time longer.
6
5
4
R1
R3
R2
䐟
䐠
䐡
VR1
B10k
䃈
4
6
7
R1
R3
L2
䐠
䐡
䐟
VR2
B10k
䃈
Allocation Terminal
block No.
Terminal
symbol
Adjuster No.
VR1
VR2
4
5
6
4
7
6
R1
R2
R3
R1
L2
R3
䐟
䐠
䐡
䐟
䐠
䐡
External adjuster terminal block layout
Note
•
The current limit function is not activated for cycle calculation zero voltage switching control.
•
Reduces output power the amount that load rate exceeds 100% (limits current to limit value by lowering output voltage).
•
If the current limit setting device is broken while allocated to external current limit setting device (VR) by key sequence
‘
1-11. Current limit
’
setting, operation is as given in External adjuster error table 3.
•
If current limit value is 0
–
10%, the equipment operates but will operate outside guaranteed precision.
11-6. Contact input / external control input (Di)
Making the C2 and C3 terminals open-circuited/short-circuited triggers the function allocated to key sequence
‘
2-2. Di function selection.
’
However, if
is allocated to key sequence
‘
2-1. Control input type selection,
’
contact input will be given priority.
To modify the settings of Di function selection,
please make it open-circuited between the terminal C2 and C3 first.
11-6-1. Contact input
Select key sequence
‘
2-1. Control input type selection
’
.
If the C2 and C3 terminals are shorted, output is 100% regardless of control input; if they are not shorted, output is 0%.
The equipment can be turned on/off from outside. Ramp higher limit and ramp lower limit are enabled.
If input signal (voltage/current) is not applied, an input-error message is displayed. To close the message, set the ke
y sequence ‘2
-6. Input error display
setting’ to “
.
”
You can switch to
‘
3. Manual output screen group
’
during contact input.
key sequence
‘
2-2. Di function selection
’
is not displayed.
11-6-2. External control input
11-6-2-1. Manual output (by external adjuster)
Select key sequence
‘
2-1. Control input type selection
’
. Select
by key sequence
‘
2-2. Di function selection.
’
Shorting the C2 and C3 terminals enables manual operation by manual setting device using VR3, regardless of control input.
When manual output is
“
on
”
(C2 and C3 terminals shorted), you cannot switch to
‘
3. Manual output screen group.
’
When manual output is
“
off
”
(C2 and C3 terminals not shorted), you can switch to
‘
3. Manual output screen group.
’
11-6-2-2. Standby
Select key sequence
‘
2-1. Control input type selection
’
. Select
by key sequence
‘
2-2. Di function selection.
’
When the C2 and C3 terminals are shorted, output is 0% (standby status), regardless of control input.
To cancel standby, remove the short between the C2 and C3 terminals.
You cannot switch to
‘
3. Manual output screen group
’
during standby.
Note:
“
Standby
”
refers to the following state:
Output is 0%.
The status display flashes on the screen prior to standby.
Alarm output maintains the same status prior to standby.
11-6-2-3. HB alarm output disable
Select key sequence
‘
2-1. Control input type selection
’
. Select
by key sequence
‘
2-2. Di function selection.
’
Shorting the C2 and C3 terminals disables HB alarm output only (off). The alarm is not output even if it is triggered. Other alarms are however
output if triggered.
HB alarm output is enabled if the C2 and C3 terminals are not shorted.
External adjuster error table 3
VR1/VR2
Output
ձ
Break
100%
ղ
Break
0%
ճ
Break
0%
